OTRC: Nicole Kidman opens up about baby name and surrogacy

Nicole Kidman shocked a few fans when she revealed earlier this month that her family welcomed a new addition via a surrogate mother.

The baby, named Faith Margaret Kidman Urban, was born on December 28 at Nashville's Centennial Womens Hospital. She is the biological daughter of both Kidman and Urban and was born through a gestational carrier.

"We just decided that this was our thing together," the actress told E! News about why she and husband Urban decided to keep quiet. "It kind of just perpetuated itself, and so then at the end we just went, 'OK. We'll make an announcement.'"

As for the baby's name, Kidman says they named her Faith "because we needed to have that through the whole pregnancy, actually. I mean, that's what it required -- a lot of faith." She added, "Margaret's my grandmother's name. She had her last baby at 49! So she's my inspiration."

The new addition to the family joins older sister Sunday Rose, 2, and Kidman's two adopted children from her marriage to actor Tom Cruise - Isabella, 18, and Connor, 16.

Kidman, 43, and country music singer Urban, also 43, were married on June 25, 2006.